Computer-aided design (CAD) software allows a user to construct and manipulate complex three-dimensional (3D) models. A number of different modeling techniques can be used to create a 3D model. These techniques include solid modeling, wire-frame modeling, and surface modeling. Solid modeling techniques provide for topological 3D models, where the 3D model is a collection of interconnected topological entities (e.g., vertices, edges, and faces). The topological entities have corresponding supporting geometrical entities (e.g., points, trimmed curves, and trimmed surfaces). The trimmed surfaces correspond to the topological faces bounded by the edges. Wire-frame modeling techniques, on the other hand, can be used to represent a model as a collection of simple 3D lines, whereas surface modeling can be used to represent a model as a collection of exterior surfaces. CAD systems may combine these and other modeling techniques, such as parametric modeling techniques. Parametric modeling techniques can be used to define various parameters for different features and components of a model, and to define relationships between those features and components based on relationships between the various parameters.
A design engineer is a typical user of a 3D CAD system. The design engineer designs physical and aesthetic aspects of 3D models, and may be skilled in 3D modeling techniques. The design engineer creates parts and may assemble the parts into a subassembly. An assembly is designed using parts and subassemblies.
When modeling electromechanical parts, a design engineer may design a wiring system that is quite complex with thousands of required connections between hundreds of different connectors and items of equipment. To define the required connections in a wiring system, an electrical design engineer typically creates schematics or from-to connection lists. From-to connection lists contain data that specifies details about the connections. From-to connection lists can be generated by commercially available electrical CAD systems. Alternatively, connections may be entered manually into a spreadsheet format.
An electrical design engineer needs to understand what wiring connections to make, what connectors to use, where to locate the connectors, and what parts and subassemblies need to be connected. Wires are not just draped across various parts and subassemblies; wires are bundled together to create a wiring harness. The design engineer needs to find the optimum path through the equipment and decide where to run all of the wires without clashing with other objects. The bundles also may need to be regularly fastened to the equipment to prevent the bundles from moving and potentially fouling other equipment.
Conventionally, designing electrical connections includes building a physical mockup or prototype of a product. Then, using a schematics or a from-to list of connections, the wiring system is physically built into the mock-up. Connectors are fixed in the appropriate places and wires are physically inserted. The wires may be grouped together into bundles, which are held together by tape, ties, or coverings. The wiring system is then removed from the mock-up, placed on a large sheet of paper, and traced to create a harness drawing. The harness drawing is then used as a template to manufacture the wiring system.
Presently, commercially available 3D modeling tools can be used to create wiring systems without building a physical mock-up of a product. Such tools replace the cumbersome and time-consuming task of, and save the expense related to creating mock-ups.
Connections in an electrical system typically run between pins of multi-pin connectors. Thus, for each multi-pin connector there are numerous potential connections. Commercially available 3D modeling tools may display each individual pin-to-pin connection resulting in a rat's nest of lines representing every single connection. Harnessing the wires and routing the wire bundle through a harness covering helps to simplify the graphical image of an electromechanical 3D model.
Ratsnests have long been used for electronic layout for PCB design and for electrical design and are currently used for electrical harness design and modeling. Typically, a ratsnest is generated for every connection, is represented by straight lines, and is used as a visual guide only. Disadvantages of generating ratsnests include the load placed on computer resources to process and draw every connection, the lack of visual clarity that can result from displaying a complex wiring system, and the absence of a automated mechanism to aid in the creation of the physical manifestation of the required routes from the ratsnests.
Replacing the need to create a physical mock-up by providing a means to create a virtual mock-up, and doing so without excessively burdening available computing resources and while helping design engineers easily transition to work efficiently within a 3D CAD environment would be advantageous to electrical design engineers who may be unfamiliar with 3D CAD systems. Moreover, a mechanism that simplifies the task of designing a wiring system design and that clearly represents the wiring system would enhance productivity.